Am researching a conversion plan for a 40' pusher school bus. I like the idea of sticking with Cummins because of the reputation, availability of parts and "reasonable prices" (for the older engines). I would like to stay away from the new engines because of the exorbitant prices for parts - especially electronics. I have been poking around a lot of forums and have come up with this combination. Does this seem like it will do the trick? I plan on doing a lot of interstate traveling so would like the bus to cruise at least 65 mph without sounding like it would blow up. 80 would be awesome - speed limit in Montana, Nevada, N Dakota, Idaho is 75 or 80 in places, but I can live with 65. Does this seem reasonable? I am hoping that the 8.3 has enough extra power to enable it to be durable as well as efficient, also that by being Cummins, I will be able to find support at almost every truck stop in North America.